Vitamin Deficiency Symptoms You Should
Pay Attention To

Written by Kathleen Morrison
Medically Reviewed by Andrea Sleeth WHNP-BC, MSCP

Key takeaways

• Fatigue, brain fog, hair loss, and muscle aches can all be early warning signs of vitamin deficiencies.
• Vitamins like D, B12, and iron play crucial roles in energy, immunity, mood, and overall well-being.
• At-home testing kits or routine bloodwork can give a clear picture of your nutrient levels.
• Eating a variety of colorful whole foods, protein, and fortified options helps cover vitamin gaps naturally.
• Spotting patterns, tracking symptoms, and acting early empowers you to support your health before small issues escalate.

Here’s the thing, your body’s really good at telling you what it needs… You just have to know how to listen. Loads of Americans are running low on at least one essential vitamin, and most people have no clue.

Those random energy crashes, weird mood dips, or breakouts that just won’t quit? They might be your body’s way of waving a little “hey, something’s missing!” flag.

The good news: spotting nutrient deficiency signs isn't actually hard. You can start by checking in with how you feel day to day—think things like tiredness that won’t budge, hair shedding like crazy, or getting sick more often than usual. From there, you can chat with a healthcare provider about simple blood tests that check your vitamin levels (like vitamin D, B12, or iron). Some pharmacies even offer easy at-home testing kits, so you can get answers without ever changing out of your PJs.

And if you’re the kind of person who likes to stay ahead of things (we see you, planner queen), keeping up with yearly bloodwork is a total game-changer. It can help you catch any gaps early and help keep your body feeling balanced, energized, and ready for… Well, whatever life throws your way.

What is a vitamin deficiency?

When your body isn’t getting enough of the vitamins it needs, things can start to feel a little off. Vitamin deficiencies happen when your body doesn’t get (or can’t absorb) enough of certain nutrients, and they can sneak up slowly over time.

You can think of vitamins like the behind-the-scenes crew keeping everything running smoothly—energy levels, mood, skin health, even your sex drive. When one of them goes MIA, you’ll notice. Thankfully, it's usually manageable once you know what’s going on.

The vitamins your body needs

There are two main types of vitamins:

• Fat-soluble vitamins (A, D, E, and K): These hang out in your body’s fatty tissues and liver. You don’t need them every single day, but too much can build up over time.
• Water-soluble vitamins (B vitamins and C): Your body uses what it needs and flushes out the rest, so you’ve got to keep topping them up regularly.
  

Each one has its own superpower:

Vitamin A supports your vision and immune system,

The Bs keep your energy and mood steady,

And vitamin D is basically sunshine in vitamin form (literally made when your skin gets sun).

Since your body can’t make all vitamins on its own, getting them from food or supplements is key to keeping you feeling your best.

How vitamin gaps can happen

There are a bunch of reasons your vitamin levels might dip, and most of them are way more common than you’d think:

• Eating mostly processed or convenience foods (hey, we’ve all been there).
• Digestive issues that make it harder for your body to absorb nutrients.
• Certain life stages—like pregnancy or aging—that change your vitamin needs.
• Specific medications that mess with how your body uses or absorbs vitamins.

You don’t have to overhaul your whole diet to fix vitamin and mineral deficiencies; you just need to know where the gaps are. Once you do, small tweaks (or a quick chat with a healthcare provider about supplements) can help you get back to feeling balanced, energized, and like your best self again.

Common symptoms of vitamin deficiencies

Your body always sends signals when something’s off. The trick is learning how to listen. Feeling constantly tired, moody, achy, or just a little “off” could mean your body’s missing out on key vitamins.

It’s not always dramatic, either. These signs creep in slowly, so it’s easy to blame them on stress, busy schedules, or getting older. But your body’s just trying to tell you it needs a little extra support.

Your energy dips (like, bad)

If you’re running on fumes, no matter how much coffee you drink, your body might be short on the nutrients that keep your energy systems humming. Low vitamin D, B12, or iron are top culprits, and each one messes with your energy in a different way.

Vitamin D helps your muscles function and keeps your bones strong, but it also impacts mood and immunity. When levels dip, you might feel sluggish, achy, or like you just can’t shake that “blah” feeling. People who spend most of their time indoors, live in cloudy climates, or have darker skin are more likely to have low D.

Vitamin B12 is your body’s oxygen delivery specialist. Without enough, your red blood cells don’t develop properly, meaning less oxygen makes it to your tissues... Cue the exhaustion. You might notice fatigue that feels bone-deep, shortness of breath, or even a racing heartbeat when you’re just sitting around.

Iron is the ultimate energy carrier. It’s what helps your red blood cells move oxygen throughout your body, keeping everything—from your brain to your muscles—running smoothly. When you’re low, it’s like your internal battery never fully charges. You might feel dizzy, weak, or out of breath doing things that used to feel easy. Heavy periods, pregnancy, and certain diets (especially vegetarian or vegan) can make low iron more likely.

If you’re constantly tired, don’t just power through it. It might be time for a simple blood test to see what your vitamin levels are doing.

You have aches that won’t quit

Muscle aches and bone pain are classic signs of vitamin D deficiency, and they feel different from your regular post-workout soreness. The pain tends to show up in your lower back, hips, or legs and feels dull and deep. That’s because vitamin D helps your body absorb enough calcium; without it, bones soften and muscles weaken, making daily movement feel harder, and possibly leading to secondary hyperparathyroidism in severe cases.

If standing up from a chair or climbing stairs feels tougher than it used to, your vitamin D might need a boost.

You feel tingles, weakness, or brain fog

B12 isn’t just about energy; it helps keep your nervous system sharp. When levels drop too low, you might feel tingling in your hands or feet, muscle weakness, or even changes in balance and coordination. It can also affect mood and focus, causing brain fog or forgetfulness that feels frustratingly random.

If you’re vegetarian, vegan, over 50, or taking certain medications like metformin or acid reducers, you’re more likely to experience B12 deficiency because your body either isn’t getting enough or can’t absorb it properly.

Your hair and nails are sending SOS signals

Your hair and nails are surprisingly honest about what’s going on inside. Hair falling out more than usual? Nails breaking or peeling like they’ve given up? That could be your body hinting at low iron, biotin, or vitamin D levels.

Iron deficiency, especially, hits women hard—it can make you feel weak and tired while also stealing your shine. Vitamin C helps here too since it boosts collagen production (that’s the stuff that helps support nail strength and elasticity).

Your immune system feels shot

If you’re catching every cold that goes around, your immune system might be waving a vitamin D flag. This nutrient helps your body fight infections and calm inflammation—basically, it keeps your defenses balanced. Low D levels can make it harder to bounce back when something’s going around.

The bottom line

Your body doesn’t suddenly “crash” when it’s low on vitamins, it drops clues first. Fatigue, mood changes, muscle aches, brittle nails, and brain fog can all be little red flags asking you to check in. Instead of guessing, get real answers.

At-home vitamin and hormone testing can help you find out what your body actually needs (without awkward appointments or waiting rooms).

Foods rich in essential vitamins

You don’t need a fancy wellness plan or pricey powders to get the vitamins your body craves. Real food can totally do the job.

When you build meals around whole, colorful ingredients, you’re not just getting vitamins, you’re also giving your body a boost of fiber, antioxidants, and other natural goodies that help everything work better together. Try to make your plate look like a rainbow. The more colors, the more nutrients you’re getting—and it keeps meals way more fun and satisfying.

Greens

Dark leafy greens are the ultimate multitaskers. Spinach gives you folate, vitamin K, and vitamin A, while kale brings vitamin C to the party. Toss them into your smoothies, stir them into pasta, or sauté them with garlic for an easy side... There’s really no wrong move here.

And don’t forget your colorful veggie besties. Orange veggies like sweet potatoes and carrots give you beta-carotene (that’s where your body gets vitamin A), while red bell peppers are loaded with vitamin C—even more than a glass of OJ, with less sugar. Basically, the more color on your plate, the more your body thrives.

Protein

Protein isn’t just about keeping you full; it’s also where some of your most important vitamins hang out. Chicken breast gives you B6 and niacin for energy. Lean beef delivers iron and B12 to keep your blood and brain happy. Eggs? They’re basically nature’s multivitamin, packed with vitamins A, D, E, and B12.

And if you love seafood, fatty fish like salmon, mackerel, and sardines are your vitamin D go-tos. Just one small serving of salmon gives you almost a full day’s worth. Bonus: you’ll also get omega-3s, which your body (and brain) will absolutely thank you for.

Fortified foods and dairy products

Fortified foods, like breakfast cereals or plant-based milks, quietly step up with added vitamins D and B12, which is great if you’re vegan or dairy-free. Greek yogurt gives you a protein and calcium combo that supports muscle and bone health, while whole grains sneak in extra B vitamins that white bread just doesn’t have.

The key is balance, not perfection. A few mindful swaps (like going for fortified almond milk or throwing spinach into your eggs) can seriously level up your nutrition game and your energy.

How to check for vitamin deficiency

If your body’s been feeling off, it might be time to see what’s going on under the hood. The easiest way to check for a vitamin deficiency is through a simple blood test. You can do it the classic way (book a quick visit with your doctor) or keep things low-effort with an at-home testing kit.

At-home tests can measure common vitamin levels like D, B12, and iron—all without leaving your couch. Once you’ve got your results, you can talk to a healthcare provider (online or IRL) about what your body needs and how to get your levels back on track.

Feeling good starts with knowing the numbers

Your body is always sending you little signals—fatigue, mood swings, hair shedding, or achy muscles—and sometimes it’s just trying to say it needs a little nutritional TLC. Checking for vitamin deficiency symptoms gives you the scoop on what’s going on inside, so you can feel like yourself again instead of running on empty.

Whether you go old-school with a quick doctor visit or keep it low-key with an at-home testing kit, knowing your levels helps you take action with confidence. And once you’ve got the results, Wisp makes it easy to chat with a healthcare provider online and figure out what your next steps are — discreet, convenient, and all about helping you feel your best.

Take the first step today: check your vitamin levels with Wisp’s at-home testing and get personalized guidance from friendly healthcare pros without leaving your couch.

This blog post is for informational and educational purposes only and should not be taken as professional advice. Always consult with a qualified professional before making any decisions based on the information provided here.

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